PKI, Digital Certificates & ASN.1 Parsing
Inspect, decode, and convert the certificate formats that underpin TLS — PEM, DER, and raw ASN.1 structures.
PEM ⇄ DER Converter
Convert between ASCII-armored PEM and binary DER
ASN.1 · DERASN.1 Parser
Decode DER hex or PEM into a readable ASN.1 tree
X.509 · TLSX.509 Certificate Parser
Decode a PEM certificate into readable fields
CSR · PKCS#10CSR Decoder
Inspect the subject and key inside a PKCS#10 CSR
PKCS#7 · P7BPKCS#7 Inspector
Decode a .p7b certificate bundle structure
PKCS#12 Extractor
.pfx / .p12 key extractor
Chain Validator
Certificate chain and root CA checks
Choosing the right pki & certificates tool
Public-key infrastructure is how the web decides which public keys to trust. An X.509 certificate binds a public key to a domain or organisation and is signed by a certificate authority; a CSR is the request you send to get one. Underneath, every certificate, key and CSR is an ASN.1 structure encoded as binary DER, usually wrapped in Base64 PEM with -----BEGIN----- lines.
Use the X.509 decoder to check a certificate's subject, SANs, validity dates and issuer before deploying it; the CSR decoder to confirm a request before submitting it to a CA; and the PEM/DER converter when a server or Java keystore wants the other format. The ASN.1 parser shows the raw structure when something won't parse. Everything is decoded locally, so it's safe to inspect certificates and requests from production.